Calcium-Ammonium Effects on Growth and Yield of Small Grains

Abstract

Abstract

Calcium (Ca++) is known to stimulate potassium (K+) and ammonium (NH+4) absorption rates by plants. Increased NH; absorption stimulates plant growth and development. However, little is known about the effect of Ca++ with NH+4 on small-grain crops. The objective of this research was to examine the effect of Ca++/NH+4 on growth and development of wheat (Triticum aestivum L.), oat (Avena sativa L.), and barley (Hordeum vulgare L.). Treatments consisted of growing small grains using complete nutrient solutions with a molar ratio of 0, 0.30, 0.60, 1.20, and 1.80 Ca++/NH+4, and a check with NO-3-N. Plants were grown in the greenhouse to seedling (30 d), intermediate (elongating, 60 d), and mature (booting, 90 d) growth stages on a NO-3 nutrient solution and then treated for 7 d with the Ca++/NH+4 fertilizer solutions. One set of plants was fertilized solely with the Ca++/NH+4 solution and another with a NO-3 fertilizer solution. The addition of Ca++ with NH+4 to small grains resulted in increased N absorption, grain yield, tiller formation, dry matter, and grain weight per unit of plant dry matter, but the extent varied with the crop. Calcium apparently caused a redirection of foliar metabolites to grains. Short-term treatments with Ca++/NH+4 at different growth stages showed the least results at the seedling stage, whereas maximum results were obtained at the intermediate growth stage (initiation of jointing) and good stimulation of plant growth and tillering at the mature (booting) stage. Calcium increased NH+4 absorption, leading to increased tillering, increased weight per head of grain produced, and consequently higher grain yields. Calcium added with NH+4-N increases plant N use efficiency by more rapid absorption, greater rates of tillering, greater metabolite deposition in seeds, and possibly increases in photosynthesis.

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